The present invention relates to an induction cooking hob with a plurality of induction coils.
An induction cooking hob includes a number of induction coils. The induction coils are arranged below a cooking surface. Further, the induction coils are arranged side-by-side to each other. Usually, the cooking surface is formed by a glass ceramic panel.
In one type of induction cooking hobs, each induction coil corresponds with a cooking zone. In order to recognize the cooking zone by the user, there is an identification symbol on the cooking surface. For example, the identification symbol is a ring covering the area above the corresponding cooking zone. Further, the identification symbol may be a cross arranged in the centre of the cooking zone.
In another type of induction cooking hobs, a plurality of small induction coils are arranged as a matrix below the glass ceramic panel. A pot detection system identifies those induction coils, which are covered by a pot. Then, a control unit of the cooking hob activates those induction coils, which are completely or partially covered by the pot. This system is efficient, if the bottom area of the pot is bigger than the areas of the induction coils. However, if the bottom area of the pot is equal as or smaller than the areas of the induction coils, then the pot may only cover small parts of neighboured induction coils. In this case, either the pot detection system does not recognize the pot, or the area of the activated induction coils is much bigger than the bottom area of the pot. Thus, this concept is only suitable for pots with a bottom area clearly larger than the area of the induction coils.
EP 2 192 820 A1 discloses a cooking hob with a plurality of induction coils arranged in a grid. According to one example, a part of the cooking surface comprises smaller induction coils that the remaining cooking surface. In said part of the cooking surface the induction coils are arranged as a matrix with three lines and three columns. The central induction coil of said matrix is marked by an identification symbol on the cooking surface. The identification symbol is a small cross above the centre of the central induction coil or a ring arranged concentrically to the induction coil. However, an exact arrangement of cooking pots is not possible, when the bottom area of the pot is bigger than the dimension of the identification symbol.